噴火湾およびその周辺海域におけるスケトウダラ子魚の分布とじ生物環境

Abstract

Form the end of 1979 to the early spring of 1980, the spawning ground of walleye pollock Theragra chalcogramma (PALLAS) was formed in the northeastern area from Shiraoi to Mukawa in contrast to that in recent years. The eggs spawned were transported toward the bay and many of them hatched befor they reached the inner area of the bay. The main food organisms of the larvae at the initial feeding stage were the eggs and nuaplii of copepods and most of them in the early spring were produced by the spawners of Pseudocalanus minutus in this study area. During the same period, the surface water of the Oyashio current was found only at the enerance of the bay, and the Tsugaru Warm Water occupied the inner area of the bay. For this reason, P. munutus were concentrated at the entrance of the bay and the distribution pattern of P. minutus coincided with that of walleye pollock larvae.